Combo PET-CT Scans Can Spot Hidden Cancers

TUESDAY Jan. 12, 2010 -- A combination whole-body PET-CT scan is more accurate than some other commonly used tests in detecting cancer in patients with neurologic symptoms, according to U.S. researchers.

So-called "paraneoplastic neurologic disorders" can occur in people with lung, breast, ovarian and other types of cancer when cancer-fighting antibodies mistakenly attack nervous system cells. Cancers that cause neurological symptoms are often small, restricted to one site and not detected until autopsy, the Mayo Clinic researchers explained.

Routine non-invasive cancer examinations may prove inconclusive in such cases. "These standard evaluations include physical examination; computed tomography of the chest, abdomen and pelvis; mammography in women; and testicular ultrasonography and prostate-specific antigen testing in men," wrote Andrew McKeon and colleagues.

They analyzed the medical records of 56 patients with suspected paraneoplastic neurologic disorders who underwent standard evaluations that did not detect cancer. The patients then underwent whole-body PET-CT, a combination of positron emission tomography (PET) and computed tomography (CT) .

Those scans detected abnormalities suggestive of cancer in 22 patients. Of those, 10 had cancer diagnoses confirmed by biopsy or another method. Of these cancers, two were in the thyroid, one in the tonsil, three in the lungs, one in the colon and three were cancerous lymph nodes with unknown primary cancer sites.

Nine of the 10 cancers were early-stage, and the patients underwent early treatment. After a median follow-up of 11 months, seven patients had cancer remission and five had improvement in neurologic symptoms.

The study was published online Jan. 11 in advance of the March print issue of the journal Archives of Neurology.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about paraneoplastic disorders.

Posted: January 2010


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